Television (TV) viewing has traditionally been one-dimensional; either live TV viewing or viewing at the present. With the introduction of the Digital Video Recorder (DVR), users are able to pause Live TV or schedule recordings for later viewing. DVR technology has limitations including that each household needs to have a physical hard disk on the set-top box to pause/fast-forward/rewind Live TV or schedule recordings, the user needs to remember to schedule the recording if the user wants to view it later, parallel recordings are limited to the hardware or software of the device, and the number of shows that can be stored is limited by the storage on the device.
Trick modes (e.g., fast-forward, rewind, and pause) are a common feature of digital video systems that simulate the visual feedback of traditional fast-forward, rewind, and pause operations performed in analog video systems. Trick modes may be implemented by either including in the video stream only a subset of frames or having a separate stream for each different speed supported (e.g., a stream that supports normal speed playback, another stream that supports 2× normal speed playback for fast-forwarding, etc.).
Restart TV is a service to allow the user to timeshift within channels to restart in-progress programs that the user has just tuned to and are not in a local buffer of the user's client device. Thus, restart TV allows users to view previously aired programming without requiring local storage of that video. Restart TV is distinct from video on demand (VoD) service. The programs available for viewing in restart TV are those that aired in a relatively short amount of time in the past (e.g., the last 72 hours) whereas the programs available for viewing in a VoD service are programs that may have aired many weeks, months, or years ago. In addition, the programs available for viewing in restart TV are typically only available for a relatively short period of time (e.g., 72 hours) whereas programs available for viewing in VoD are typically available for a relatively longer period of time (e.g., weeks, months, or years).
The channels that support restart TV service are typically indicated in a program guide to allow the user to navigate to view past programs. Restart TV eliminates the limitation of parallel recordings, pre-scheduling recordings, and storage constraints. There may be limitations on the Restart TV service such as not allowing trick modes.